Class structure and class formation are two crucial aspects of class. The former relates to differences in market positions and the latter concerns social factors such as interaction, mobility and class action. This paper is based on Swedish data covering the period from 1975 to 1995. Analysis reveals a persistent class hierarchy and that there is no trend towards declining class differences regarding market position. The situation is better described as being in a state of non-linear flux. However, one persistent trend is discernible; class explains less and less of the variance in wage income. Looking at class formation there is a decline over time in class-homogeneity. Most Swedes are mobile in the sense that they end up in a class position different from their father's. A growing majority of all marriage is also class mixed. However, although classes generally lack homogeneity, social boundaries still exist, i.e., tendencies for immobility and class homogeneous marriage. In relation to the Фclass-is-dying hypothesis, the results generally indicate the continuing relevance of class, although the view of classes as homogenous social groups is increasingly troublesome over time.